Achievers 1 WBCS (Main) Exam. Paper–IV Practice Set Answers with Explanation 1. (b) 6. (d) Both assertion and reason are false. Regeneration 2. (c) Phobia is a kind of intense fear from something. is not itself a strategy but rather the shedding e.g., hydrophobia, ailurophobia is fear of cats, off of any organ is a strategy to avoid predation. astraphobia is fear of thunder and lightning, The strategy to regenerate the body parts from achluophobia is fear of darkness. Neurosis is the pre-existing tissue or adult stem cells. This less severe than mental illness and is normal to actually involves the de-differentiation of the overcome worry, fear, anxiety and feeling of mature cells to make them a sort of stem cells insecurity. This can also develop due to again which can then differentiate to make the maladaptive habits. Hypochondria is a condition lost part. The later strategy is different than in which there is undue concern about health the strategy involved in escaping predation. by a person about himself. Insomnia is lack of 7. (b) An enzyme is basically a protein which acts sleep over many nights. xÄy!‰þ¦þy¢Å like a catalyst in the metabolic reaction and the 3. (b) Cigarette smoke contains N-nitrosodimethylene juice of the pancreas is basically composed and causes accumulation of toxics in lungs from three enzymes trypsin, amylase and lipase. and arteries to block the passages. Mustard 8. (b) Progesterone is released from the female gas, chemically known as Bis (2-chloroethyl) gonads. It has roles in the female menstrual sulphide, blocks lungs and affects respiration cycle, pregnancy and embryogenesis. Growth as it is a strong mutagen and Carcinogen. hormone or somatropin or somatropin, is a Asbestos affects lungs and pleural membranes peptide hormone that stimulates growth, cell as it is made up of tiny fibers that enter into reproduction and regeneration in humans and lungs when breathed in. Vinylchloride is an other animals, the pituitary gland secretes this organochloride, H2C = CHCl is highly toxic, hormone. The pancreas secretes insulin that flammable and carcinogenic and lungs are regulates the sugar metabolism in the body. affected. xÄy!‰þ¦þy¢Å Cortisol is released from the zona fasciculata 4. (c) Jaundice is a result of increased bile pigments of the adrenal cortex in response to stress. in the blood. Defects of heart valves leads to 9. (b) Electroencephalography (EEG) is the recording stenosis, in which the blood vessels are of electrical activity along the scalp. EEG narrowed abnormally so, there is abnormal measures voltage fluctuations resulting from blood sounds. Highly allergic infection and ionic current flows in neurons of the brain. inflammation of nose is known as Rhinitis. Electrocardiography (ECG) is a transthoracic Paralysis is the loss of motor functions due to interpretation of the electrical activity of the damage to nervous system. heart over a period of time detected by 5. (a) Leucocytes are white blood cells. These electrodes attached to the surface of the skin comprise of neutrophils which provide and recorded external device. Electroo- protection to the body through phagocytosis culography (EOG) is a technique of measuring of bacteria and thus act as scavengers. The the corneoretinal standing potential existing basophils are the granulocytes which contain between the front and the back of the human histamines and heparin. Heparin thins blood to eye. Electromyography (EMG) is a technique prevent clotting. Histamines dilate the blood for evaluating physiologic properties of muscles. vessels and increase the permeability of 10. (a) xÄy!‰þ¦þy¢Å capillaries. Monocytes are of two types namely 11. (b) Milch animals are those animals which are macrophages and dendritic cells. Acidophils take source of milk, e.g. cow, goat, buffalo. Foot- up role in anti-allergic reactions and wound and mouth disease, caused by Aphthae healing. The lymphocytes are B cells, T cells epizooticae is an infectious disease that affects and natural killer cells. These are mainly involved cloven-hoofed animals. Anthrax is an acute in the immune responses by producing specific infectious disease caused by the bacterium antibodies. Bacillus anthracis. Blackleg, black quarter is 2 î¡ìÅ éôé 8– £z¢%Ä éôé 10 ‹y˜%ëûy!îû– 2021 xÄy!‰þ¦þy¢Å an infectious bacterial disease caused by to it in comparison to the kinetic energy of Clostridium chauvoei affecting cattle, sheep and heavy body. goats. Cowpox is caused by cowpox virus and 22. (b) It has been calculated in the theory of the is infectious. chapter i.e., 12. (b) Washing soda is sodium salt of carbonic acid. mg v2 h It occurs as a crystalline heptahydrate, which R1 1 , on heating looses its water to form a white 2 rga powder monohydrate. This process is called mg v2 h efflorescence. and R 1 , R < R . xÄy!‰þ¦þy¢Å 2 2 rga 1 2 Na CO · 7H Oheat Na CO · H O + 6H O 2 3 2 2 3 2 2 23. (a) A steam engine converts the heat energy 13. (a) Electron – 9.1 × 10–31 kg produce by coal into kinetic energy and this Proton – 1.00728 u xÄy!‰þ¦þy¢Å produces electricity which further light the lamp Neutron – 1.00867 u and convert electricity into heat and light. 14. (d) Silver forms a black thin layer of silver sulphide 24. (c) When spoon is dropped gently, its tangential on reaction with hydrogen sulphide which is speed is equal to the speed of spaceship, and present in trace amount in the atmosphere. so it revolves like a satellite. 15. (a) Consumption of high concentration of fluoride 25. (d) A - (r); B - (p); C - (s); D - (q) causes mottling of teeth or fluorosis. 26. (c) Velocity of object w.r.t mirror = 10 cm/s 90 2+ 16. (c) In Sr , So velocity of image w.r.t you 38 = 2 × 10 = 20 cm/s. Atomic number = no. of protons = 38 27. (a) Properties of different types of magnets are; Since it has lost 2e– so no. of electrons = 38 Artificial magnet- short lived, permanent – 2 = 36 magnetlong lived, Temporary magnet- induced Atomic mass = no. of protons + no. of neutrons magnet, earth as a magnet- last for infinitely 90 = 38 + no. of neutrons long period. 90 – 38 = no. of neutrons xÄy!‰þ¦þy¢Å 28. (c) When a light wave passes from one medium to 52 = no. of neutrons other, its frequency remains constant but its Hence, no. of neutrons = 52, no. of protons = speed and wavelength change. 38. xÄy!‰þ¦þy¢Å 29. (d) Refractive index of a medium depends on its 17. (d) Formic acid – Ant’s sting nature. Refractive index (µ) is also given by Tartaric acid – Tamarind sini Oxalic acid – Spinach µ = sin r Citric acid – Orange where i = angle of incidence 18. (b) CaO + H O Ca(OH) + heat 2 2 r = angle of refraction Ca(OH) formed will be basic thus pH > 7. 2 Thus, µ depends on the angle of incidence. 19. (b) Scientist Discovery C Moseley – Atomic number Again, µ 0 where C is the velocity of c 0 Chadwick – Neutron light in vacuum and c is the velocity in a Millikan – Measurement of charge of an medium. We know that frequency remains electron. xÄy!‰þ¦þy¢Å constant when light passes from one medium Aston – Mass spectrograph to other, therefore, 20. (c) Solar energy is not responsible for green house effect instead it is a source of energy for the 0 xÄy!‰þ¦þy¢Å plants and animals. The colour of light depends on wavelength. 21. (d) Because they have equal momenta, hence equal Thus, µ depends on the colour of the incident mv, the heavy body will move very slowly and ray. the light body will move very quickly. As Kinetic 30. (d) The medical name for long-sightedness is 1 energy is mv2. Thus the speed of the light hypermetropia, sometimes called hyperopia. 2 Eyesight problems, such as hypermetropia, are body will be high giving a higher kinetic energy also known as refractive errors. Long sight Achievers 3 leads to problems with near vision, and the areas. However, the present forest cover in eyes may commonly become tired. Distance India is around 21-22 %. vision (long sight) is, in the beginning, often 39. (b) CO2 is the largest contributor towards global clear. Long sight can be corrected by glasses warming, followed by methane, CFCs and N2O. or contact lenses, or sometimes ‘cured’ with 40. (b) Arihant is a class of nuclear–powered ballistic laser eye surgery. xÄy!‰þ¦þy¢Å missile submarine. xÄy!‰þ¦þy¢Å 31. (b) Forests are renewable natural resources and AWACS, abbreviation of Airborne Warning and enhance the quality of environment by Control System, is a mobile, long–range providing the Oxygen needed to sustain life on surveillance and control centre for air defence, the earth. Although both assertion and reason developed by the U.S. Air Force, is mounted are correct statements but reason is not the on Boeing 707 aircraft. correct explanation of the assertion. Atlas – Centaur is an American expendable 32. (a) Plants are called primary producers because launch system. It is the first production rocket plants produce their food themselves through stage to use cryogenic propellent. Nag is a the process of photosynthesis. third generation fire–and–forget” anti-tank 33. (d) As we go higher in the trophic levels through missile of India. the food chain, the loss of energy due to 41. (a) Indian Space Research Organisation (ISRO) is respiration as well as metabolic activities headquartered in Bengaluru. The Inter– successively increase. University Centre for Astronomy and So, there occurs the transference of only 10% Astrophysics (IUCAA) is located in Pune, India.